The substances, including cobalt and radioactive isotopes of manganese and iron, were identified in samples collected in Rovaniemi, Kuopio, and Imatra. According to authorities, such materials can be generated during nuclear power production and may occasionally be released into the atmosphere in very small quantities, for example during routine operations or maintenance. Finland currently operates two nuclear power plants: the Loviisa Nuclear Power Plant in the south of the country and the Olkiluoto Nuclear Power Plant on the west coast.